a recorded or recordable recording medium such as a compact disc (CD) or a digital versatile disc (DVD) has been considered to record identification information (ID) peculiar to a recording medium. This identification information can be used as an identifier for deciding whether this recording medium is an authentic one or an illegally copied one.
However, if any other information can be added to the medium identification information, the added information (hereinafter referred to as “relevant information”) can be used to realize a variety of services peculiar to the recording medium. That is, medium information comprising the relevant information in addition to the medium identification information can be used also as an identifier for enjoying the various services.
The various services, if information recorded on a recording medium has been encrypted, for example, refer to capability of accessing a managing server which manages medium information to thereby acquire from the managing server key information required for decryption of the information. This is because, also in a case where information is to be recorded on a recording medium as encrypted, if key information (decryption key etc.) for decryption of the information is recorded on the same recording medium, the encrypted information can be decrypted using the key information when the recording medium is illegally copied. Storing key information of encrypted information separately from the recording medium allows such illegal utilization thereof to be eliminated.
Alternatively, information indicating a classification of a recording medium may be added as relevant information, so that, if a classification of a medium onto which information is copied from this recording medium is different from a classification of this original medium, this copied medium can be decided to be an illegally copied one, thus contributing to protection of copyright.
If this relevant information is available, it is possible to further acquire information (contents) related to information recorded or to be recorded, that is, music information, information about artists etc. related to music information, image information (still images, moving images), or digital information such as program data which is used in a computer.